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AME5297 Datasheet, PDF (9/14 Pages) Analog Microelectronics – Step-Down DC/DC Converter | |||
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AME
AME5297
3A, 18V, 500KHz Synchronous
Step-Down DC/DC Converter
When using tantalum or electrolytic capacitors, the ESR dominates the impedance at the switching frequency. For
simplification, the output ripple can be approximated to:
VOUT
=
VOUT
f ÃL
Ã
1â VOUT
VIN
à R ESR
Setting the Output Voltage
The output voltage is using a resistive voltage divider connected from the output voltage to feedback pin. It divides the
output voltage down to the feedback voltage by the ratio:
VFB
=
VOUT
Ã
R2
R1 + R2
The output voltage is:
VOUT
=
0.8 Ã
R1 + R2
R2
n Typical Application Circuits
VIN
4.5V~16V
Ren1
18K
CIN2
NS
CIN1
22uF
Ren2
10K
C3
1uF
C5
22nF
IN
BST
AME5297
EN
SW
R4
10â¦
C4
0.1uF
L1
4.7uH
VCC
SS
FB
GND
R1
40.2K
R3
33K
R2
12.7K
VOUT
3.3V/3A
C6
15pF
R5
0â¦
COUT 1
22uF
COUT2
22uF
VOUT(V)
1.0
1.2
1.8
2.5
3.3
5.0
R1(Kâ¦)
20.5
30.1
40.2
40.2
40.2
40.2
R2(Kâ¦)
82.0
60.4
32.4
19.1
12.7
7.68
R3(Kâ¦)
82
82
56
33
33
33
L(µH)
1.5
1.5
2.2
3.3
4.7
6.8
CIN(µF)
22
22
22
22
22
22
COUT(µF)
22x2
22x2
22x2
22x2
22x2
22x2
Rev. A.05
9
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